Semiconductor Device

1. A semiconductor device comprising: a plurality of pixels each comprising: a light emitting element; a protection circuit; a first transistor for controlling the amount of current flowing in the light emitting element; and a second transistor for controlling a current supply to the light emitting element in accordance with a video signal, wherein the light emitting element, the protection circuit, the first transistor, and the second transistor are connected in series between a first power supply and a second power supply, and the protection circuit comprises at least one of a resistor element, a capacitor element and a rectifier element.

2. The semiconductor device according to claim 1 , wherein the rectifier element is a diode.

3. The semiconductor device according to claim 1 , wherein the rectifier element is a transistor whose gate electrode and drain electrode are connected to each other.

4. The semiconductor device according to claim 1 , wherein the pixel comprises a switching transistor for controlling a video signal input.

5. The semiconductor device according to claim 1 , wherein the pixel comprises an erasing transistor for discharging electric charges of a capacitor element disposed between a gate electrode and a source electrode of the second transistor.

6. The semiconductor device according to claim 1 , wherein a ratio of a channel length L 1 /a channel width W 1 of the first transistor to a channel length L 2 /the channel width W 2 of the second transistor is set as L 1 /W 1 :L 2 /W 2 =5 to 6000:1.

7. The semiconductor device according to claim 1 , wherein the first transistor and the second transistor have the same conductivity.

8. The semiconductor device according to claim 1 , the semiconductor device is used for an electronic apparatus selected from the group consist of a display device, a digital still camera, a note book personal computer, a mobile image reproducing device, a goggle type display, a video camera, and a mobile phone.

9. A semiconductor device comprising: a plurality of pixels each comprising: a light emitting element; a protection circuit; a first transistor for controlling the amount of current flowing in the light emitting element; and a second transistor for controlling a current supply to the light emitting element in accordance with a video signal, wherein the light emitting element, the protection circuit, the first transistor, and the second transistor are connected in series between a first power supply and a second power supply, and the protection circuit is a resistor element connected in series to a pixel electrode.

10. The semiconductor device according to claim 9 , wherein the pixel comprises a switching transistor for controlling a video signal input.

11. The semiconductor device according to claim 9 , wherein the pixel comprises an erasing transistor for discharging electric charges of a capacitor element disposed between a gate electrode and a source electrode of the second transistor.

12. The semiconductor device according to claim 9 , wherein a ratio of a channel length L 1 /a channel width W 1 of the first transistor to a channel length L 2 /the channel width W 2 of the second transistor is set as L 1 /W 1 :L 2 /W 2 =5 to 6000:1.

13. The semiconductor device according to claim 9 , wherein the first transistor and the second transistor have the same conductivity.

14. The semiconductor device according to claim 9 , the semiconductor device is used for an electronic apparatus selected from the group consist of a display device, a digital still camera, a note book personal computer, a mobile image reproducing device, a goggle type display, a video camera, and a mobile phone.

15. A semiconductor device comprising: a plurality of pixels each comprising: a light emitting element; a protection circuit; a first transistor for controlling the amount of current flowing in the light emitting element; and a second transistor for controlling a current supply to the light emitting element in accordance with a video signal, wherein the light emitting element, the protection circuit, the first transistor, and the second transistor are connected in series between a first power supply and a second power supply, and the protection circuit is a capacitor element which discharges or charges electric charges built up on a pixel electrode.

16. The semiconductor device according to claim 15 , wherein the pixel comprises a switching transistor for controlling a video signal input.

17. The semiconductor device according to claim 15 , wherein the pixel comprises an erasing transistor for discharging electric charges of a capacitor element disposed between a gate electrode and a source electrode of the second transistor.

18. The semiconductor device according to claim 15 , wherein a ratio of a channel length L 1 /a channel width W 1 of the first transistor to a channel length L 2 /the channel width W 2 of the second transistor is set as L 1 /W 1 :L 2 /W 2 =5 to 6000:1.

19. The semiconductor device according to claim 15 , wherein the first transistor and the second transistor have the same conductivity.

20. The semiconductor device according to claim 15 , the semiconductor device is used for an electronic apparatus selected from the group consist of a display device, a digital still camera, a note book personal computer, a mobile image reproducing device, a goggle type display, a video camera, and a mobile phone.

21. A semiconductor device comprising: a plurality of pixels each comprising: a light emitting element; a protection circuit; a first transistor for controlling the amount of current flowing in the light emitting element; and a second transistor for controlling a current supply to the light emitting element in accordance with a video signal, wherein the light emitting element, the protection circuit, the first transistor, and the second transistor are connected in series between a first power supply and a second power supply, the protection circuit is a protection transistor whose gate electrode and drain electrode are connected to each other, and the drain electrode or a source electrode of the protection transistor is connected to the first power supply.

22. The semiconductor device according to claim 21 , wherein the pixel comprises a switching transistor for controlling a video signal input.

23. The semiconductor device according to claim 21 , wherein the pixel comprises an erasing transistor for discharging electric charges of a capacitor element disposed between a gate electrode and a source electrode of the second transistor.

24. The semiconductor device according to claim 21 , wherein a ratio of a channel length L 1 /a channel width W 1 of the first transistor to a channel length L 2 /the channel width W 2 of the second transistor is set as L 1 /W 1 :L 2 /W 2 =5 to 6000:1.

25. The semiconductor device according to claim 21 , wherein the first transistor and the second transistor have the same conductivity.

26. The semiconductor device according to claim 21 , the semiconductor device is used for an electronic apparatus selected from the group consist of a display device, a digital still camera, a note book personal computer, a mobile image reproducing device, a goggle type display, a video camera, and a mobile phone.

27. A semiconductor device comprising: a plurality of pixels each comprising: a light emitting element; a protection circuit; a first transistor for controlling the amount of current flowing in the light emitting element; and a second transistor for controlling a current supply to the light emitting element in accordance with a video signal, wherein the light emitting element, the protection circuit, the first transistor, and the second transistor are connected in series between a first power supply and a second power supply, and the protection circuit is a diode one electrode of which is connected to a pixel electrode and the other electrode of which is connected to a third power supply.

28. The semiconductor device according to claim 27 , wherein the pixel comprises a switching transistor for controlling a video signal input.

29. The semiconductor device according to claim 27 , wherein the pixel comprises an erasing transistor for discharging electric charges of a capacitor element disposed between a gate electrode and a source electrode of the second transistor.

30. The semiconductor device according to claim 27 , wherein a ratio of a channel length L 1 /a channel width W 1 of the first transistor to a channel length L 2 /the channel width W 2 of the second transistor is set as L 1 /W 1 :L 2 /W 2 =5 to 6000:1.

31. The semiconductor device according to claim 27 , wherein the first transistor and the second transistor have the same conductivity.

32. The semiconductor device according to claim 27 , the semiconductor device is used for an electronic apparatus selected from the group consist of a display device, a digital still camera, a note book personal computer, a mobile image reproducing device, a goggle type display, a video camera, and a mobile phone.